The present invention relates to a monitoring system for electronic analysis of images and sounds. More particularly, the present invention relates to apparatus and methods for generating and putting out a matrix of image frames and/or sound segments in a unique visual presentation.
Television images are typically formed as a series of scanned discrete image frames which are projected on a frame by frame basis on a suitable screen (e.g. the light generating phosphor display screen of a cathode ray tube). The persistence of the phosphors, and the insensitivity of the human eye cause an integration of the discrete frames into the appearance of a continuously moving image, usually the desired result.
There are some situations where it is desirable to inspect television images on a frame by frame basis at a slowed or still frame rate. In order to use television equipment which, for example, repeats each frame approximately 30 times per second some form of frame store must be used. The frame store records the frame to be inspected at the real time (30 Hz) rate and then reads it back over and over again, usually at the same 30 Hz rate. One widely available form of frame store is the helical scan video recorder wherein the helix dimensions and the tape velocity (and number of rotating scanning heads) are designed to store a single frame (or field) on a single diagonal track of the tape. Freeze frame viewing is achieved by stopping the tape velocity and enabling the rotating head to repeatedly scan and read out the frame. Slowed motion is also possible with some momentary loss of synchronization by slowing tape velocity from its normal rate.
More sophisticated frame stores are known and employ both analog and digital techniques in rotating disk and solid state frame stores. With the advent of high speed high capacity integrated circuit semiconductor memory, together with high speed analog to digital to analog conversion circuits and techniques, digital frame stores have supplemental analog stores for many applications, such as special effects generators in television studios wherein multiple images from multiple video sources may be combined digitally into a single frame time and put out as a viewable composite frame of multiple images. Split screen display is one example.
Film editing has typically been carried out on a frame by frame (image by image) basis. In the case of sprocketed film an editing viewer is placed between two manually operable reels. The film is then inspected to locate edit points. A complication arises if the film includes a sound track which requires normal operating velocity for intelligible playback. "Squawkboxes" emit low, guttural sounds and noises as the film moves over a sound track reader at very low speeds.
Video tape editing has employed both real time and slowed frame techniques. Electronic edit points are added to a control track, and automatic editing by insertion and deletion is carried out in accordance with the manually inserted control track edit points.
Positive editing of film and video tape with respect to sound content has been more difficult to carry out, since there has been no practical way heretofore to view a frozen frame or frames and hear at regular playback rate the audio content which accompanies the frozen frame(s).
One known approach to providing a video editing viewer (which applicants do not concede is a prior art approach), is described in United Kingdom Patent Application GB No. 2,136,653 A published Sept. 19 1984. The methods described therein required complex convolution circuitry and resulted in less than a satisfactory display of multiple miniature frames which were concentrated in a narrow vertical strip down the viewing screen. Most of the usable display screen area was unused in this other apprach. Also, no attempt was even made to play audio back at real time rates which corresponds to the television frame being frozen on the screen.
It is known to add time codes to picture frames, whether film or video. One standardized approach is the SMPTE time code, promulgated by the Society of Motion Picture and Television Artists. SMPTE time coding has replaced sprocket hole counting and film rate and has enabled the synchronization or recording systems such as visual, analog tape and digital. Application of SMPTE time codes to generation of music for sound tracks is proposed in an article by Ms Suzanne Ciani entitled "How to use SMPTE time code to create video music" published in Video Systems Magazine, July 1981 issue, pp. 32-33.
In some specialized applications such as the transfer of images from film to tape, called "Telecine", it is essential to detect each scene change so that the colors present in the new scene may be corrected. Heretofore, this telecine conversion operation has been carried out manually with each new scene requiring freeze framing of the film transport and with new color correction parameter being then entered, along with the SMPTE time code into a color correction computer which automatically adjusts the hue and intensity of the colors of the video playback during a second pass in the telecine conversion. The telecine conversion is carried out only after each scene change has been located and color corrected manually.
Other specialized applications giving rise to the present invention include slow frame analysis of X-ray images in such fields as diagnostic tomography.
Thus, a hitherto unsolved need has arisen for an improved monitoring system for video and/or audio images.